The world population has grown to point where mass production of the foods that we consume is no longer a luxury but a requirement. Local farmers, providing food and food products directly to the marketplace, cannot meet the demands of modern society. The food supply chain now incorporates very large, complex farms and high speed and very high volume processing plants to satisfy the need for mass processing and production of food. Maintaining a safe food supply chain relies on the dedication of those working in the supply chain, the processing plants, and also on the third party oversight of various federal agencies whose regulations support and mandate food safety.
With two major exceptions, the physical process of taking an animal from the farm to the consumer has changed very little over time. The introduction of refrigeration, and the implementation of various chemistries to help maintain sanitary conditions and to control microbiology, has given modern food processors an advantage not enjoyed by food producers of a century ago. Refrigeration and chemical intervention practices have become an integral part of food processing facility operations. These technologies have enabled the high speed, high volume output of the large processing facilities that could not have been possible in times past without significant concern for consumer safety. With large scale and continuous processing methods being employed by large processors of protein products, or any other product that is susceptible to microbiological contamination, the concern for the control of microbiology and the safety of the food supply chain is of paramount importance.
Another concern, as the demand for food products increases, is the impact on natural resources created by this demand. The ecological impact is directly affected by this growth and therefore new processes must be developed to reduce the impact any given process has on the environment. The ecological impact that a food processing plant has on the environment is no longer a passing concern but a major part of operations and planning. Entire processes are built around the control and conservation of natural resources such as water. Older, outdated and less efficient processes are being replaced at significant cost with more efficient and less wasteful processes that maximizes the utility of available resources. No longer can a plant operate without concern for the conservation and sustainability of natural resources.
Still another concern in slaughtering and processing plants is unwanted airborne microorganisms that are emitted when an animal is processed, such as poultry (i.e., turkey, duck and chicken) during shackling, killing, scalding, and picking areas. These airborne microorganisms are unwanted in the processing and packing areas of the plant because they can affect product quality and safety. They also pose a potential threat to the health and well-being of the workers in the plant. Still further, such airborne microorganisms can affect down-field processes in a processing plant, posing quality and safety concerns.
To insure that the food supply chain in modern society is maintained at the highest levels of safety for the consumer, the plant's employees, and the overall environment, there are federal agencies that monitor the processors operations so that a continually safe food supply is assured and the environmental impact and utilization of natural resources is as safe and efficient as possible. Modern food processing methods are scrutinized by government agencies to ensure compliance with safe handling and processing guidelines designed to minimize issues of food safety in the supply chain. Regulations and routine inspections of systems and processes by federal agencies such as the USDA, EPA and OSHA, mandate a government-industry alliance that helps ensure that every effort is made to deliver the safest for product possible to the consumer.
Very innovative approaches to the systems and methods used in processing facilities have been implemented to create profits for industry while maintaining low consumer cost of the final product. As new processes are developed, the federal agencies that have jurisdiction over any particular process are called upon to review the new approach and to ensure that the new innovation meets the current guidelines for safety. The higher the processors output, the higher the risk of microbiological contamination, and therefore the more innovative the processor must be to combat this ever present threat to the food chain safety. As new risks are found, federal guidelines become more stringent.
Large scale refrigeration systems, used to help control microbial growth in various processing applications, have helped the food processing industry to remain in compliance with food safety goals. Refrigeration applications and processes are implemented at various locations in the processing operation to ensure maximization of microbiology control and shelf life. Depending on the particular product being processed—beef, pork, poultry and fish for example—and the particular operation taking place, various methods of achieving this reduction in product temperature are employed. In poultry processing for example, submersion in large chilled water baths is the allowed and preferred method for the rapid reduction in carcass temperature after evisceration. Other means of accomplishing the reduction in temperature for beef or pork products are utilized that do not currently utilize a large chilled water bath for the purpose.
In industrial processing of poultry, immediately after slaughter, bleeding, hot water immersion, feather withdraw and viscera withdrawal, poultry carcasses have to be chilled to reduce their temperature from approximately 40 to 4° C., which contributes to ensuring safe products. Immersion chilling is a relatively low cost and fast cooling technique largely used in South America and North America in countries such as the United State and Brazil, two of the biggest poultry producers in the world. In this system, poultry carcasses are forced to move through stainless steel tanks containing chilled water or a mixture of ice and water. Water in the system may be agitated by introducing air into the chiller tank from air intake lines to keep bird carcasses buoyant and roiling in the chiller to ensure an even chill. These tanks may also contain antimicrobial intervention solutions to reduce and control bacteria which may compromise food safety and product shelf life. In these tanks, the carcasses are displaced by means of an endless screw in counter-current with the cooling water flow. The United States poultry industries routinely use this rapid chilling process because the United States Department of Agriculture, Food Safety and Inspection Service, demands the chilling of carcasses below 4.4° C. until 4 hours postmortem to minimize microbial growth and to preserve product quality. The cooling rate is influenced by the size, shape, and fat of the carcass, as well as by the temperature and flow pattern (and stirring level) of water inside the tanks.
The means by which this initial chill operation is accomplished in large production facilities is by feeding a continual flow of product on a belt conveyor into the lead-in section of a large chilled water tank and ensuring that the product is submerged continually, typically with a water temperature set at approximately 34° F.
In one typical method, the process incorporates a large tank fitted with a sectionalized and gated conveyor that provides separate sections where the product is loaded. The gates are mounted on a chain-type conveyor and continually move through the chilled water bath with the gates providing segregation from one load to another. The gates continuously push a load of product through the chilled water bath, from the lead-in section to the lead-out section, at a speed that is designed to provide ample dwell time for the intended cooling purpose. Another method of accomplishing the same material handling operation is the use of a large diameter auger placed in the chiller tank in lieu of the moving gates described above. The auger flights determine the volume of product that can be loaded in each section and the auger rotational speed as well as the total length of the tank determines the dwell time the product will be allowed to remain in the chilled bath.
Immersion chilling has a benefit of an increased “washing effect” which lowers the total microbial load on the birds; however, it is also a potential place for cross contamination to occur. In order to control microbiology in chiller tanks, it is a typical practice to add specialized chemistry to the tanks throughout the processing day. This specialized chemistry is known in the industry as an intervention solution. There are several antimicrobials that are approved and effective for use in the chiller to decrease pathogens, including, for instance, chlorine, peroxyacetic acid, bromine, cetylpyridinium chloride (1-hexadecylpyridinium chloride, CPC), organic acids, trisodium phosphate (TSP), acidified sodium chlorite and chlorine dioxide.
Sanitation in chiller management is critical to product quality and safety. There are many components to the chiller that if not cleaned properly can result in higher microbial load (decreased shelf-life) and higher pathogen-positive birds. Large chilled water baths (i.e., chiller tanks) are routinely cleaned by dumping the chilled water bath solutions within the chiller tank, sanitizing the chiller tank, and re-filling the chiller tank with chilled water and any intervention solution. Beyond cleaning the interior volume of the processing tanks, the large chilled water baths also often require routine cleaning or replacement of the air intake lines, which introduce air into the contents of the chiller tank during operation to stir the contents using air agitation. The air intake lines often use an unfiltered compressed air supply from another location within the processing plant. Thus, the air lines should be regularly cleaned and sanitized, or alternatively replaced, to minimize contamination of the processing tank from the introduction of microbial loads (i.e., mold, yeast and/or bacteria) from the air source into the processing tank and prevent unwanted buildup of microbial loads within the air lines.
As such, there is a need in the industry to efficiently and cost-effectively provide a source of air into the air intake lines of processing tanks that minimizes microbial loads into the processing tanks and/or a build-up of microbial loads within the air intake lines, particularly chiller tanks for poultry processing, which not only are time consuming to clean or replace and a source of lost revenue during the down-time that the chiller tank and/or air intake lines are being cleaned or replaced, but a potential source of higher microbial load (decreased shelf-life) and higher pathogen-positive birds if not properly maintained.